To unravel the mystery of acupuncture-induced analgesia, we have instituted two separate approaches. First, we have made a study of behavioral responses to noxious stimulation in monkeys trained to press a lever to escape a stimulus when the intensity reaches a painful level. We have demonstrated that acupuncture increases the threshold of pain perception in this experimental paradigm. The second approach is to record the activity of neurons in a brain region, implicated in pain perception (Nucleus parafascicularis). We have demonstrated, in the immobilized monkey, that acupuncture reduces the evoked activity of neurons in this nucleus. Our present objective is to combine these two procedures to investigate the effects of acupuncture on the evoked activity of parafascicularis neurons and concomitant lever pressing escape behavior, in response to increasing intensity levels of electrical stimulation applied to the trained unanesthetized monkey.